Kelcey Harrison, center, and Jill Costello, right, were lifelong friends, seen here with Gianna Toboni on a grade school field trip. [Photos courtesy of Kelcey Harrison]

A couple of Saturdays ago, while you were watching college football or out buying a Christmas tree, 24-year-old Kelcey Harrison was running the last 20 miles of a 3,500-mile "jog" from Times Square to her hometown of San Francisco.

Harrison, who graduated from Harvard, where she played soccer, is young, healthy and motivated. By the time she completed The Great Lung Run, she had logged 30 miles nearly every day for four months straight.

Harrison ran because she can. And because her lifelong friend Jill Costello -- who was also once young and healthy and motivated -- cannot.

On June 6, 2009, Costello, then a junior at Cal and a member of the crew team, was diagnosed with lung cancer. The disease was already at stage 4 and had spread; she was given about a year to live. Costello spent that year finishing school, earning Pac-10 Athlete of the Year honors, acting as vice president of the Panhellenic Council and doing tireless work for lung cancer charities -- all while undergoing chemotherapy.

In May 2010, doctors told Costello she could not be cured; all they could do was try to make her last few weeks more comfortable. In those last weeks she walked across the stage at graduation (with a 4.0 GPA) and helped Cal to a second-place finish at the NCAA crew championships.

"Jill was really strong," Harrison said. "She was really confident that she was gonna be the one to beat stage 4 lung cancer. She was very convincing in her argument; even at the very end we really believed she was going to be the miracle."

Costello died June 24, 2010.

Great Lung RunThe goal of the Kelcey Harrison's run across the United States was to raise $250,000 for lung cancer research. Donations are being accepted here.

Kelcey Harrison

No. 1 Cancer Killer

A young, vibrant nonsmoker, Costello was the last person anyone would expect to get lung cancer. But 20 percent of the more than 20,000 women diagnosed with the disease each year have never smoked. Lung cancer is the No. 1 cancer killer in the United States, taking more lives than colon, breast and prostate cancer combined.

Despite the staggering stats, there are no pink ribbons worn or mustaches grown in the name of lung cancer. There is, instead, a stigma that the disease is self-inflicted; an illness brought on by a life of smoking. Research and funding is limited and the five-year survival rate for lung cancer is 15.5 percent; it hasn't budged in 40 years. More than half of all people with lung cancer die within a year of being diagnosed.

Darby Anderson, the director of Jill's Legacy, said at first she didn't think Harrison would follow through with her plan to run across the country.

"I thought she was nuts," said Anderson, who was a sorority sister and close friend of Costello's. "I told her to call me back when she had an actual plan and then we would take her project from there. … [That] April I saw her in D.C. when I was there for our Jog for Jill Georgetown and she had a website, route, places to stay and was ready to actually make this happen. I was blown away."

Harrison was up early every morning to jog her 30 miles, taking a day off every 10 days or so to let her body rest. She took a break to walk every once in a while, but never stopped moving until the 30 miles were finished.

"It's just like getting up and going to work," Harrison said. "Sure there are days where it wasn't the first thing I wanted to be doing but that was my routine and my job at the time, so just gotta get up and do it."

Harrison's not sure how, but after 3,500 miles, she feels OK.

"I don't have an answer as to why I'm holding up so well," Harrison said. "It's a mystery to me just like everyone else. … People said they think I have the right motivation and someone special looking over me."

Harrison ran solo for the first six weeks of her trip, pushing her belongings in a jogging stroller and staying with hosts who would pick her up at the end of each run and drop her off the next morning where she left off. Eventually one of her friends from Jill's Legacy joined her on the road in a donated car, driving her to and from hotels along the way.

(The donated car, by the way, was a gold Chrysler 300 with 22-inch rims. When their first donated car lost its power steering the girls ended up at Oscar's Auto Salvage in New Mexico, hoping to sell it and rent one for the remainder of the trip. Instead, Henry, the shop's owner, offered his own tricked-out car for the final months of the trip.)

Kelcey Harrison

Just another day at the office

Running more than a marathon every day for four months sounds nearly impossible, but Harrison said from the start that if Costello could accomplish as much as she did in her last year of life, all while being ravaged by chemo, then a simple jog across the country was nothing.

"I spent a week with her on the road and she'd finish up her run and it was like she had just finished a day at work," Anderson said. "We would hang out, head to dinner, chit-chat and do completely normal things, except that she had just run 30 miles that day. … Kelcey has more courage and inspiration than anyone I have ever met and I am so grateful to have been able to just be a small part of this huge adventure."

The last part of The Great Lung Run was across the Golden Gate Bridge to Crissy Field. The Cal crew team, Harrison and Costello's high school crew team and other friends and family joined in for the final miles.

The official completion of Harrison's run took place last Thursday -- a celebratory cocktail party at St. Ignatius College Prep, the high school she and Costello attended. Harrison had been honoring Costello's memory with each step of her journey, but returning to a place where they grew up was difficult.

"It's not hard to think about Jill all the time because she sort of turns into this image, a legend" Harrison said. "What's hard is when you find those moments to step back and remember Jill your friend. Jill who did Halloween costumes with me for 16 years of our lives. That's where it's tough.

"It's become bigger than her, which sometimes is sad because you feel like you're forgetting a little bit of your friend, but in her last year of life that's really what she was aiming for. All of us at Jill's Legacy are really proud of what we're accomplishing but also really sad about [the reason] we're all involved in this."

Harrison will wake up this week with no miles to run, no path to follow. She's no longer interested in attending law school, but isn't quite sure what she wants to do instead.

"I'll take a little time to relax and then try to figure out what's next," she said. "I'm looking out for jobs, but I'll always be tied to our foundation and the cause of lung cancer. We'll always have jogs, bar events, restaurant things; anything to get more young people involved in lung cancer awareness. That will continue forever."